Here FocusControl works fine...
I paste here the properties of my grid, so you can try to set your
like mine, and see if works

object grdRigheContabili: TIB_Grid
Left = 0
Top = 0
Width = 959
Height = 193
CustomGlyphsSupplied = []
DataSource = dmContabili.dsrMovconTestaRighe
Align = alClient
OnDblClick = grdRigheContabiliDblClick
ReadOnly = True
TabOrder = 0
ListBoxStyle = True
CurrentRowColor = clCream
OrderingColor = clCream
StretchColumn = 'MERGE_RIGA_DESCRIZIONE'
TabMovesOut = True
end

the code is
dmContabili.qryMovconTestaRighe.FieldByName('DARE').FocusControl;

here D6 pro up2, IBO 4.2Ia, Win2000

regards
Marco Menardi